client refactored and tested (#43)

.golangci.yml

@@ -73,6 +73,7 @@ issues:
     - path: ._test\.go
       linters:
         - goerr113
+        - gocritic
         - errcheck
         - funlen
         - dupl

Makefile

@@ -10,7 +10,10 @@ GIT_TAG=`git describe --abbrev=0 2>/dev/null || echo -n "no-tag"`
 GIT_HASH=`git rev-parse --short HEAD 2>/dev/null || echo -n "no-git"`
 BUILD_AT=`date +%FT%T%z`
 
-LDFLAGS=-w -s -X main.gitHash=${GIT_HASH} -X main.buildDate=${BUILD_AT} -X main.gitVersion=${GIT_TAG}
+LDFLAGS=-w -s \
+		-X main.buildDate=${BUILD_AT} \
+		-X main.gitVersion=${GIT_TAG} \
+		-X main.gitHash=${GIT_HASH}
 
 export CGO_ENABLED=0
 

README.md

@@ -24,7 +24,22 @@ Takes all network connections from your docker containers and exports them as:
 - json stream
 - statistics (nodes, edges and listen ports)
 
-# features
+## rationale
+
+I was in need for a tool to visualize and inspect big (more than 470 containers) dockerized legacy system without any schemes and having a bare minimum of documentation.
+
+## analogs
+
+Closest analogs, i can find, that not suit my needs very well:
+
+- [Red5d/docker-autocompose](https://github.com/Red5d/docker-autocompose) - produces only `compose yaml`
+- [justone/dockviz](https://github.com/justone/dockviz) - produces only `dot`, links and ports are taken
+  from compose configuration (`links` and `ports` sections) directly, therefore can miss some of them
+- [LeoVerto/docker-network-graph](https://github.com/LeoVerto/docker-network-graph) - very same as above, build in
+  python
+- [weaveworks/scope](https://github.com/weaveworks/scope) - deprecated, no cli
+
+## features
 
 - os-independent, it uses different strategies to get container connections:
   - running on **linux as root** is the fastest way and it will work with all types of containers (even
@@ -33,20 +48,20 @@ Takes all network connections from your docker containers and exports them as:
     (i.e. for missing `netstat` binary), no connections for such container will be gathered
 - produces detailed connections graph **with ports**
 - save `json` stream once and process it later in any way you want
-- fast, scans ~400 containers in around 5 sec
+- fast, scans ~470 containers in around 5 sec
 - 100% test-coverage
 
-# known limitations
+## known limitations
 
 - only established and listen connections are listed (but script like [snapshots.sh](examples/snapshots.sh) can beat this)
 - `composer-yaml` is not intended to be working out from the box, it can lack some of crucial information (even in `-full` mode),
   or may contains cycles between nodes (removing `links` section in services may help), its main purpose is for system overview
 
-# installation
+## installation
 
 - [binaries / deb / rpm](https://github.com/s0rg/decompose/releases) for Linux, FreeBSD, macOS and Windows.
 
-# usage
+## usage
 
 ```
 decompose [flags]
@@ -83,13 +98,13 @@ possible flags with default values:
         show version
 ```
 
-## environment variables:
+### environment variables:
 
 - `DOCKER_HOST` - connection uri
 - `DOCKER_CERT_PATH` - directory path containing key.pem, cert.pm and ca.pem
 - `DOCKER_TLS_VERIFY` - enable client TLS verification
 
-# json stream format
+## json stream format
 
 ```go
 type Item struct {
@@ -155,7 +170,7 @@ example with full info and metadata filled:
 
 See [stream.json](examples/stream.json) for simple stream example.
 
-# metadata format
+## metadata format
 
 To enrich output with detailed descriptions, you can provide additional `json` file, with metadata i.e.:
 
@@ -178,10 +193,10 @@ one of provided keys, like `foo-1` or `bar1` for this example.
 See [csv2meta.py](examples/csv2meta.py) for example how to create such `json` fom csv, and
 [meta.json](examples/meta.json) for metadata sample.
 
-# clusterization rules
+## clusterization rules
 
-You can join your services into `clusters` by exposed ports, in `dot` or `structurizr` output formats.
-With clusterization rules, in `json` (order matters):
+You can join your services into `clusters` by flexible rules, in `dot`, `structurizr` and `stat` output formats.
+Example `json` (order matters):
 
 ```json
 [
@@ -213,7 +228,7 @@ type Node struct {
 
 See: [cluster.json](examples/cluster.json) for detailed example.
 
-# examples
+## examples
 
 Save full json stream:
 
@@ -245,7 +260,7 @@ Load json stream, enrich and save as `structurizr dsl`:
 decompose -load nodes-1.json -meta metadata.json -format sdsl > workspace.dsl
 ```
 
-# example result
+## example result
 
 Scheme taken from [redis-cluster](https://github.com/s0rg/redis-cluster-compose):
 
@@ -266,6 +281,6 @@ in other terminal:
 decompose -format dot | dot -Tsvg > redis-cluster.svg
 ```
 
-# license
+## license
 
 [![FOSSA Status](https://app.fossa.com/api/projects/git%2Bgithub.com%2Fs0rg%2Fdecompose.svg?type=large)](https://app.fossa.com/projects/git%2Bgithub.com%2Fs0rg%2Fdecompose?ref=badge_large)

cmd/decompose/main.go

@@ -21,6 +21,7 @@ import (
 const (
 	appName       = "Decompose"
 	appSite       = "https://github.com/s0rg/decompose"
+	linuxOS       = "linux"
 	defaultProto  = "all"
 	defaultOutput = "-"
 )
@@ -250,15 +251,7 @@ func doLoad(
 	ldr := graph.NewLoader(cfg)
 
 	for _, fn := range files {
-		fd, err := os.Open(fn)
-		if err != nil {
-			return fmt.Errorf("open %s: %w", fn, err)
-		}
-
-		err = ldr.LoadStream(fd)
-		fd.Close()
-
-		if err != nil {
+		if err := feed(fn, ldr.FromReader); err != nil {
 			return fmt.Errorf("load %s: %w", fn, err)
 		}
 	}
@@ -273,14 +266,25 @@ func doLoad(
 func doBuild(
 	cfg *graph.Config,
 ) error {
-	cli, err := client.NewDocker()
+	opts := []client.Option{
+		client.WithClientCreator(client.Default),
+	}
+
+	mode := client.InContainer
+
+	if runtime.GOOS == linuxOS && os.Geteuid() == 0 {
+		opts = append(opts, client.WithNsEnter(client.Nsenter))
+		mode = client.LinuxNsenter
+	}
+
+	cli, err := client.NewDocker(append(opts, client.WithMode(mode))...)
 	if err != nil {
-		return fmt.Errorf("docker: %w", err)
+		return fmt.Errorf("client: %w", err)
 	}
 
 	defer cli.Close()
 
-	log.Println("Starting with method:", cli.Kind())
+	log.Println("Starting with method:", cli.Mode())
 
 	if err = graph.Build(cfg, cli); err != nil {
 		return fmt.Errorf("graph: %w", err)

go.mod

@@ -1,6 +1,6 @@
 module github.com/s0rg/decompose
 
-go 1.21.0
+go 1.21.1
 
 require (
 	github.com/antonmedv/expr v1.15.1

internal/builder/dot.go

@@ -1,5 +1,7 @@
 //go:build !test
 
+// i/o here, nothing to test
+
 package builder
 
 import (

internal/builder/json_test.go

@@ -53,7 +53,7 @@ func TestJSON(t *testing.T) {
 
 	ldr := graph.NewLoader(cfg)
 
-	if err := ldr.LoadStream(bytes.NewBuffer(jnode)); err != nil {
+	if err := ldr.FromReader(bytes.NewBuffer(jnode)); err != nil {
 		t.Fatal("load err=", err)
 	}
 
@@ -108,7 +108,7 @@ func TestJSONAddEdge(t *testing.T) {
 
 	ldr := graph.NewLoader(cfg)
 
-	if err := ldr.LoadStream(bytes.NewBufferString(raw)); err != nil {
+	if err := ldr.FromReader(bytes.NewBufferString(raw)); err != nil {
 		t.Fatal("load err=", err)
 	}
 
@@ -166,7 +166,7 @@ func TestJSONAddBadEdges(t *testing.T) {
 
 	ldr := graph.NewLoader(cfg)
 
-	if err := ldr.LoadStream(&buf); err != nil {
+	if err := ldr.FromReader(&buf); err != nil {
 		t.Fatal("load err=", err)
 	}
 

internal/builder/sdsl.go

@@ -1,5 +1,7 @@
 //go:build !test
 
+// i/o here, nothing to test
+
 package builder
 
 import (

internal/builder/stat_test.go

@@ -51,7 +51,7 @@ func TestStat(t *testing.T) {
         }
         `
 
-	if err := ldr.LoadStream(bytes.NewBufferString(raw)); err != nil {
+	if err := ldr.FromReader(bytes.NewBufferString(raw)); err != nil {
 		t.Fatal("load err=", err)
 	}
 
@@ -137,7 +137,7 @@ func TestStatCluster(t *testing.T) {
         }
         `
 
-	if err := ldr.LoadStream(bytes.NewBufferString(raw)); err != nil {
+	if err := ldr.FromReader(bytes.NewBufferString(raw)); err != nil {
 		t.Fatal("load err=", err)
 	}
 

internal/builder/yaml.go

@@ -1,5 +1,7 @@
 //go:build !test
 
+// i/o here, nothing to test
+
 package builder
 
 import (

internal/client/defaults.go

@@ -0,0 +1,55 @@
+//go:build !test
+
+package client
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os/exec"
+	"strconv"
+
+	"github.com/docker/docker/client"
+	"github.com/s0rg/decompose/internal/graph"
+)
+
+func Default() (rv DockerClient, err error) {
+	rv, err = client.NewClientWithOpts(
+		client.FromEnv,
+		client.WithAPIVersionNegotiation(),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("docker: %w", err)
+	}
+
+	return rv, nil
+}
+
+func Nsenter(
+	ctx context.Context,
+	pid int,
+	proto graph.NetProto,
+	parse func(io.Reader) error,
+) (
+	err error,
+) {
+	arg := append([]string{"-t", strconv.Itoa(pid), "-n"}, netstat(proto)...)
+	cmd := exec.CommandContext(ctx, nsenterCmd, arg...)
+
+	pipe, err := cmd.StdoutPipe()
+	if err != nil {
+		return fmt.Errorf("pipe: %w", err)
+	}
+
+	defer pipe.Close()
+
+	if err = cmd.Start(); err != nil {
+		return fmt.Errorf("exec: %w", err)
+	}
+
+	if err = parse(pipe); err != nil {
+		return fmt.Errorf("parse: %w", err)
+	}
+
+	return nil
+}